1. Field of the Invention
The present invention relates to an earphone device having a biological information (or living body information) measuring apparatus structured to facilitate insertion of an earphone into a user's ear and to absorb vibration generated by external artificial movement before and after insertion of the earphone.
2. Description of the Related Art
Generally, a biological information measuring apparatus measures biological information about the bloodstream of a human body, such as pulse, heart rate, and the like. Products embodying these devices have various shapes and sizes, and some of them have been miniaturized to be portable or integrally incorporated within other products.
For example, there is a device having a pulse sensor embedded in a wrist watch. As the user contacts the pulse sensor provided in the wrist watch with a finger tip, a pulse is optically detected by the pulse sensor and a pulse rate is displayed on a display unit of a main body of the wrist watch.
Such a conventional biological information measuring apparatus generally uses an electrocardiogram (ECG) sensor, which measures a pulse rate by detecting an ECG signal with a multi-polar electrode. Also introduced is an optical sensor which measures biological information by radiating light onto a skin surface of a human body using a light emitting diode (LED) and detecting light output from the skin surface by the action of scattering in the human body using a photo diode (PD).
As disclosed in International Publication No. WO 2005/034742, which is incorporated herein by reference, the conventional biological information measuring apparatus is structured such that a pulse measuring sensor, one of transmissive optical sensors, for a part of a human ear known as the tragus is in the shape of a nipper and thus presses the tragus. Like a general nipper, the pulse-measuring sensor also includes two arms, a pivot, and a spring.
Recently, research is being conducted to downsize biological information measuring apparatuses, and as part of this, a device for mounting the measuring apparatus using the biological structure of a user's ears has been developed.
A biological information measuring apparatus connected to an earphone may operate according to the following schemes: measuring biological information through the skin in a transmissive manner by binding the measuring apparatus in a lobe by means of an additional apparatus independently of the earphone; measuring biological information through the skin in a transmissive manner by binding the measuring apparatus in an auricle by means of an apparatus independent of the earphone; measuring biological information through the skin in a transmissive manner by binding the measuring apparatus in a tragus portion; and especially for a wireless earphone, measuring biological information in a contact portion between the wireless earphone and skin except for an ear portion in a refractive manner.
However, the foregoing conventional schemes may have some problems. That is, if a sensor unit is completely separated from an earphone structure, a user may need an additional wire-connected device and do the troublesome work of mounting the sensor unit after inserting the earphone into the ear.
To solve the above-described problems, the sensor unit may be integrated into the earphone. In this case, however, the user may feel discomfort during or after wearing the sensor unit and measurement may be totally impossible due to significant signal distortion caused by artificial movement generated during times when the user is moving, such as during exercise.
As such, when the biological information measuring apparatus is mounted in the earphone, it performs measurements on the user's auricle portion in the transmissive manner, whereby much noise may be generated by the movement of the earphone and the head portion. Generally there is no way to prevent the movement of the earphone and the head portion due to the existence of only an ear hook portion to secure the earphone to the user's ear.
As shown in FIG. 1, a neckband type earphone 1 in a shape similar to a headphone where speakers are mounted on both ends of a neckband behind the head of a user has been developed in an effort to solve the foregoing problems.
The neckband type earphone 1 includes a neckband portion 2, sub neckband portions 3 provided at both ends of the neckband portion 2, and speaker portions 4 provided on the sub neckband portions 3. The neckband portion 1 includes a battery unit 5, a sensor controller 6, and a radio frequency (RF) unit 7.
The neckband type earphone 1 also includes a biological information measuring apparatus, which includes a sensor unit 8 having an LED 8a and a PD 8b. 
However, as shown in FIG. 2, the conventional neckband type earphone 1 is hung on a tragus portion 101 of a user's ear 100, and thus the speaker portions 4 cannot be completely inserted.
To address this problem, a high-elasticity wire, which is easily deformed, is inserted into the sub-neckband portions of a conventional neckband type earphone, such that they are freely deformed during insertion of the earphone into a user's ear. However, when the user having worn the earphone strenuously exercises, for example, runs or walks, the wire is likely to be deformed by shock and vibration perpendicular to the user's moving direction. As a result, the earphone is separated from the user's ear and thus the biological information measuring apparatus cannot measure the user's biological information. Moreover, after the earphone is used for a long time, the sub-neckband portions are prone to damage.
To extract a biological signal, a sensor unit is generally positioned in a body contact portion, which may be a tragus, an entry to an internal auditory canal, or a temple, which contacts a speaker portion. However, near the temple, the user's hair and hair follicles as well as skin are present, resulting in a limitation in biological signal extraction using light.
If measurement is performed in the tragus, or through entry to the internal auditory canal of the user's ear, the earphone may not be easily inserted due to the size of the speaker portion having the sensor unit mounted thereon, in spite of removal of the influence of hair or the like.
Accordingly, there is a need for an apparatus which facilitates insertion of an earphone into a user's ear by using rotation, and delivers only a minimal part of a shock and vibration to the earphone, caused by strenuous movement after insertion of the earphone, by absorbing the shock and vibration, thereby guaranteeing convenience in wearing a biological information measuring apparatus and improving the performance of the biological information measuring apparatus.